Jane I've had a brilliant experience finding my own voice singing with women't barbershop chorus. The nearest one to 'ull I that I can see rehearse Wednesday evenings in Leeds:
http://www.whiterosettes.org.uk/aboutus.html

The costuming is usually over the top for contest (bling city) but reasonable for community performances. The teaching skill of directors and section leaders in this genre of choral singing is very high as a rule, all the more so in this chorus, given their high achievements in LABBS (google it).

The number one goal of sound production in the barbershop world is to help singer find their freely produced resonance. Choruses typically offer personal vocal instruction by qualified people (director, section leader(s), assistants or others in the chorus may be qualified). Rehearsals typically include work on what is called "craft", i.e. components of how to sing, how to perform. The lessons I've learned in this genre are totally transferable to my folk singing because they focus on one's own resonance and on effective story-telling that communicates well to the audience.

Worth a visit...even if that kind of music is not for you (but do go hear it before you jump to stereotype conclusions!) they can still steer you towards a teacher who won't try to shoe-horn you into a false voice, to teachers who help people sing without tension and with resonance.